MEMS devices frequently operate based upon reactions to applied forces, pressures, and loads. In many systems, the manner in which a membrane or structure is deformed or deflected is used as a sensing or actuating function. Such deformation includes expansion and contraction, longitudinal bending, transversal bending, and torsional bending. Specific structural deformation is required in some specialized devices. For example, in Coriolis-effect-based MEMS vibratory gyroscopes incorporating a vibrating-plate topology concept, translational motion of a proof mass in drive direction is relied upon to provide accurate sensing functions. Any motion of the proof mass that is not purely within the drive direction can affect the accuracy of the device.
In many devices which incorporate a proof mass, movement of the proof mass is detected using electrostatic forces induced by capacitive comb drives or parallel plates and applied to either the proof mass or the proof mass frame, depending upon the particular device design. Movement of the proof mass along the drive direction is then sensed or effected while the proof mass is supported by a mechanical support such as a beam. Both comb drive and parallel plate designs are subject to various limitations. Comb drives, for example, are susceptible to high actuation voltage and micro-fabrication process complexity while parallel plates are susceptible to high actuation voltage, non-linearity over travel distances, and pull-in effect. Accordingly, design flexibility and performance of these types of devices can be limited. Additionally, these devices typically exhibit decreasing performance as the size of the devices is further miniaturized.
What is needed therefore is a system and method of forming a system that can accomplish and/or sense microstructure deflection which is simple to manufacture. It would be beneficial if the system and method of forming a system could be accomplished using known MEMS manufacturing processes. It would be further beneficial if the system and method of forming a system could be easily adapted to smaller platforms.